The present invention relates to a technology which can permit the detection accuracy in a defect detection optical apparatus to be corrected speedily and easily in order to optimize the aptness of geometrical dimension of defects and to suppress a variation in detection accuracy.
In semiconductor production process, if a foreign matter is present on a semiconductor substrate (wafer), it causes a defect such as faulty insulation or short-circuit of wiring to occur. With miniaturization of semiconductor devices advanced, even a minute foreign matter causes defective dielectric strength of capacitors or breakdown of gate oxide films. The foreign matter as above will be generated from moving components of a conveyance apparatus or from human bodies or through reactions with process gas in a processing apparatus or will mix with chemicals or materials, thus being supposed to mix in various conditions.
In one of techniques for detection of foreign matters on a wafer, a defect as represented by a foreign matter can be inspected by irradiating a laser beam on the wafer, detecting a ray of scattering light from the foreign matter or the like deposited on the wafer and comparing a result of inspection of the wafer with that of a wafer of the same kind inspected immediately precedently (see JP-A-62-89336).